Abstract
Understanding the effects of climatic upheavals during the Early to Late Cretaceous transition is essential for characterizing the tempo of tectonically driven landscape modification and biological interchange; yet, current chronostratigraphic frameworks are too imprecise, even on regional scales, to address many outstanding questions. This includes the Mussentuchit Member of the uppermost Cedar Mountain Formation, central Utah (southwestern United States), which could provide crucial insights into these impacts within the Western Interior Basin of North America yet remains imprecisely constrained. Here, we present high-precision U-Pb zircon dates from four primary ash beds distributed across ~50 km in central Utah that better constrain the timing of deposition of the Mussentuchit Member and the age of entombed fossils. Ages for ash beds are interpreted through a combination of Bayesian depositional age estimation and stratigraphic age modeling, resulting in posterior ages from 99.490 + 0.057/−0.050 to 98.905 + 0.158/−0.183 Ma. The age model predicts probabilistic ages for fossil localities between the ashes, including new ages for Moros intrepidus, Siats meekerorum, and several undescribed ornithischian dinosaur species of key interest for understanding the timing of faunal turnover in western North America. This new geochronology for the Mussentuchit Member offers unprecedented temporal insights into a volatile interval in Earth’s history.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 962-967 |
| Number of pages | 6 |
| Journal | Geology |
| Volume | 51 |
| Issue number | 10 |
| DOIs | |
| State | Published - 2023 |
Bibliographical note
Funding Information:We thank members of the 2012–2022 North Carolina Museum of Natural Sciences and Field Museum of Natural History–University of Minnesota expeditions along with R. Cifelli and S. Madsen for relocating historical sites and staff of the Price Field Office, Bureau of Land Management, Utah State Office, and Utah Geological Survey for permitting. Financial support was provided by Stellenbosch University’s Department of Earth Sciences, Canyonlands Natural History Association, and National Science Foundation awards 1925973 and 1925884. We also thank S. Verryn and XRA Analytical and Consulting and L. Herzog for logistic support. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Furthermore, we thank senior editor W. Clyde along with reviewers E.M. Roberts, A. Möller, and anonymous reviewers who significantly improved this manuscript’s earlier versions.
Publisher Copyright:
© 2023 Geological Society of America.